Project Summary/Abstract Approximately 114 million surgical and procedure-based wounds occur annually worldwide, including 36 million from surgery in the U.S. Damages to delicate soft tissues, such as lung, liver, and blood vessels, are particularly challenging to repair. When these tissues are punched for biopsy or injured during procedures, they must be reconnected surgically using sutures, staples, or implantation of surgical meshes. Despite their common use in clinics, these mechanical methods are associated with inevitable tissue damages caused by deep piercing and ischemia. These methods are also time-consuming, demand surgeon's skills during the surgeries, and might cause post-surgical complications such as infection. To resolve these issues, various types of surgical materials have been used for sealing, reconnecting tissues, or attaching devices to tissues. Despite the emergence of several surgical sealants, the biomaterials used as sealants/adhesives often have some drawbacks that limit their applications, such as low mechanical flexibility, toxicity effects or toxic degradation products, poor adhesive strength, and inability to control bleeding. Therefore, none of them meet all the necessary needs to replace sutures and staples. An ideal surgical sealant is required to be flexible to adapt with dynamic movement of native tissues, have excellent biocompatibility and controlled biodegradability, provide high adhesive strength and burst pressure particularly in the presence of body fluids, and demonstrate hemostatic properties to prevent extensive blood loss. In this proposal, we aim to engineer a novel, highly adhesive and hemostatic hydrogel-based surgical sealant from a visible light activated, modified recombinant human protein methacryloyl tropoelastin (MeTro) and hemostatic silicate nanoparticles (SNs). We will physically blend the engineered MeTro hydrogels with SNs to form MeTro/SN composite hydrogels with highly adhesion and enhanced hemostatic performance. We will then evaluate the function of the engineered surgical material as a hemostatic sealant in both small and large animal models. Our preliminary data suggests that this material is superior to the existing products in the market and may generate a paradigm-shifting surgical material that may not require sutures due to its superior mechanical, adhesive, and hemostatic properties. The engineered highly adhesive and hemostatic surgical sealant can be potentially used to stop air leakages after lung surgery and also support new tissue formation to repair the defected sites. Due to the highly tunable properties of the engineered composite hydrogels, it is expected that this system can also be used in various procedures such as anastomoses, cardiovascular surgeries, and wound closure.